ASTRONOMICAL PHENOMENA AND PROGRESS. 



53 



changes in the direction of motion in the line 

 of sight as determined by spectroscopic ob- 

 servations made at the Royal Observatory, 

 Greenwich, from 1875 to 1885, during opposi- 

 tion, which occurs in the winter months : 



Miles. 



1875-' 7 6. .Sirius moving from us at the rate of 21 ! per sec. 

 lS76-'77. Sirius moving from us at the rate of 21 -1 per sec. 

 1877-' 78. .Sirius moving from us at the rate of 23'0 per sec. 

 1879-'80..Siriiis moving from us at the rate of 15' 1 per sec. 

 1380-'31 .Sirius moving from us at the rate of 11 '3 per sec. 

 lS31-'82.. Sirius moving from us at the rate of 2'1 per sec. 

 1882-'33 . . Sirius moving toward us at the rate of 4' T per sec. 

 1883-'S4. . Sirius moving toward us at the rate of 19 '4 per sec. 

 1884 -'85. . Sirius moving toward us at the rate of 21 5 per sec. 



At the present time Aldebaran, Capella, and 

 Castor are receding, while Pollux, Sirius, Arc- 

 turus, and Alpha Cygni are, at different veloci- 

 ties, approaching our system. 



Dr. Gould announces that the eighth-magni- 

 tude star, in R. A. 23 h - 58 m - 1'85 8 -, Dec. 37 

 58' 18-76" for 1875-0 = No. 1584 in hour XXIII 

 of the Cordoba Zone Catalogue, has the very 

 large annual proper motion, in a direction 66 

 46' to the east of south, of over 6'2" of a great 

 circle. But two stars whose proper motion 

 exceeds the one just described are known 

 viz., Groombridge 1830, and Lacaille 9352. 

 That of the former amounts to 6-976", and of 

 the latter to 6-9565". The last mentioned, 

 since it was catalogued by Lacaille in 1752, has 

 moved over an arc of 15' 30". 



Periodic Changes in the Spectrum of Beta Lyra. 

 Herr von Gothard has contributed to the " As- 

 tronomische Nachrichten " an elaborate paper 

 on the changes seen in the spectrum of Beta 

 Lyra during the past year. He secured thirty 

 observations between the middle of February 

 and the middle of November, and found the 

 bands of D 3 to vary periodically from an almost 

 dazzling brightness to disappearance. As this 

 is a variable star, changing in somewhat less 

 than thirteen days from 5 '5 to 6 -5 magnitude, 

 it suggests the question whether the sodium 

 lines in all variables do not change periodically, 

 and also whether the period of change coincides 

 with the period of variability. 



New Nebulae. This department of practical 

 astronomy has, for many years, been sadly 

 neglected. Lately, however, a fresh interest 

 has been awakened in the minds of a few as- 

 tronomers possessing large telescopes, and it 

 is to be hoped that ere long the study of the 

 nebulaa may be prosecuted with some of the 

 old-time vigor shown in the labors of the Her- 

 schels, D'Arrest, Lassel, Rosse, and Tempel. 

 Only the latter two survive, and they, together 

 with M. Stephan, of Marseilles, France, and Dr. 

 Lewis Swift, of the Warner Observatory, Roch- 

 ester, N. Y., are the only astronomers now en- 

 gaged in a systematic search for new nebulas. 

 M. Stephan has recently contributed to the 

 " Comptes Rendus " a catalogue of one hun- 

 dred new ones, discovered by himself, reduced 

 to the epoch of 1885-0. This and former 

 catalogues published by him at various times 

 contain about five hundred new nebulas. Dr. 

 Swift, since assuming the directorship of the 



Warner Observatory, has devoted his entire 

 time to the search for nebulas and comets, be- 

 ginning his quest for the nebulae on July 9, 

 1883. His first catalogue, containing approx- 

 imate positions of one hundred new nebula? 

 reduced to the epoch of 1885-0, may be found 

 in the " Astronomische Nachrichten," followed 

 by the publication in the same journal of a 

 second list of a like number. 



So thoroughly has the sky been explored by 

 comet-seekers that it may be truthfully averred 

 that, north of 25 south decimation, there is not 

 a single undiscovered nebula as bright as Her- 

 schel's class I (bright). Of his class II (faint) 

 there may remain a very few. Of his class 

 III (very faint) there are probably several 

 thousands that have escaped detection, which, 

 including those already known, would bring 

 the entire number up to about ten thousand. 

 Since July 8, 1885, forty-six have been discov- 

 ered at the Warner Observatory. In his first 

 published catalogue, Dr. Swift has included 

 twelve that are the property, by right of origi- 

 nal discovery, of his son Edward, a lad of thir- 

 teen years. 



Dr. Ralph Copeland's stellar nebulas, like the 

 stars, are mere points, and can only be deter- 

 mined by the spectra they give. During the 

 autumn of 1884 five such objects were discov- 

 ered by him at Dun Echt Observatory, Scot- 

 land, with the star spectroscope after the meth- 

 od of Prof. E. C. Pickering, of Harvard Col- 

 lege Observatory, who has also discovered quite 

 a number of the same class of objects. 



Occupations. The only star brighter than a 

 3 magnitude occulted by the moon during 

 1885 is Alpha Tauri (Aldebaran), which to 

 some part of the earth disappeared behind the 

 moon thirteen times, or once in each month 

 except September, when it was twice occult- 

 ed ; but three of the thirteen occultations were 

 visible at Washington. Owing to the peculiar 

 position of the moon's nodes, Aldebaran will 

 have been successively occulted 44 times, viz., 

 in 1884 4 times, in 1885 13 times, in 1886 12 

 times, in 1887 12 times, and in 1888 3 times. 

 To the astronomer, occultations of stars by the 

 moon are of great value, as they enable him to 

 determine with greater accuracy the moon's 

 diameter; to learn of her many inequalities, 

 including the cause and amount of the accel- 

 eration of her mean motion, and help him to 

 answer the unsolved problem, How much of 

 this acceleration is due to a gradual decrease 

 in the eccentricity of the earth's orbit, and how 

 much to some other cause or causes ? Venus 

 suffered one occupation in 1885, Mercury three, 

 Jupiter three, and Uranus ten, none of which 

 were visible at Washington. 



New Star in the Great Nebula in Andromeda. On 

 September 1 the astronomical world was star- 

 tled by the telegraphic announcement that on 

 the previous evening Prof. Hartwig, of the Ob- 

 servatory of Dorpat, Russia, had discovered a 

 new star in the center of the great nebula in 

 Andromeda. This is the most conspicuous 



